Method and apparatus for transmitting and receiving downlink control channel

ABSTRACT

A method of receiving a downlink control channel at a user equipment (UE) in a wireless communication system is disclosed. The method includes receiving information on a resource element group (REG) bundle size and information on a size of a matrix for interleaving a plurality of REGs configuring at least one control channel element (CCE) through a higher layer, determining the matrix for interleaving the plurality of REGs based on the information on the size of the matrix and the information on the REG bundle size, interleaving the plurality of REGs bundled into one or more REG bundles according to the REG bundle size using the matrix, and receiving the downlink control channel based on the plurality of interleaved REGs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/065,561, filed on Nov. 5, 2018, now allowed, which is a NationalStage application under 35 U.S.C. § 371 of International Application No.PCT/KR2018/004921, filed on Apr. 27, 2018, which claims the benefit ofU.S. Application No. 62/521,323, filed on Jun. 16, 2017, U.S.Application No. 62/505,852, filed on May 13, 2017, and U.S. ApplicationNo. 62/491,927, filed on Apr. 28, 2017. The disclosures of the priorapplications are incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a method and apparatus for receiving adownlink control channel and, more particularly, to a method andapparatus for receiving a plurality of resource element groups (REGs)included in a control channel element (CCE) configuring a downlinkcontrol channel in a state of being mapped to one or more physicalresources.

BACKGROUND ART

As more and more communication apparatuses require more communicationtraffic, a next-generation 5G system, which is further improved ascompared to an existing LTE system, is required. In the next-generation5G system called NewRAT, communication scenarios are classified intoEnhanced Mobile BroadBand (eMBB), Ultra-reliability and low-latencycommunication (URLLC), and Massive Machine-Type Communications (mMTC).

The eMBB is a next-generation mobile communication scenario having highspectrum efficiency, high user experienced data rate, high peak datarate, etc., the URLLC is a next-generation mobile communication scenariohaving ultra-high reliability, ultra-low latency, ultra-highavailability, etc. (e.g., V2X, Emergency Service, Remote Control), andthe mMTC is a next-generation mobile communication scenario having lowcost, low energy, short packets, massive

DISCLOSURE Technical Problem

The present invention provides a method and apparatus for receiving adownlink control channel.

Technical tasks obtainable from the present invention are non-limited bythe above-mentioned technical task. And, other unmentioned technicaltasks can be clearly understood from the following description by thosehaving ordinary skill in the technical field to which the presentinvention pertains.

Technical Solution

The object of the present invention can be achieved by providing amethod of receiving a downlink control channel at a user equipment (UE)in a wireless communication system including receiving information on aresource element group (REG) bundle size and information on a size of amatrix for interleaving a plurality of REGs configuring at least onecontrol channel element (CCE) through a higher layer, determining thematrix for interleaving the plurality of REGs based on the informationon the size of the matrix and the information on the REG bundle size,interleaving the plurality of REGs bundled into one or more REG bundlesaccording to the REG bundle size using the matrix, and receiving thedownlink control channel based on the plurality of interleaved REGs.

The plurality of REGs may be interleaved in units of one or more REGbundles.

The information on the size of the matrix may be information on a sizeof rows or columns of the matrix.

The size of the columns or rows of the matrix may be determined based onthe size of the rows or columns of the matrix and the number of REGbundles included in a control resource set (CORESET) configured in theUE.

If the determined size of the columns or rows of the matrix is not aninteger, an integer having a minimum value among integers greater thanthe determined size of the columns or rows of the matrix may bedetermined as the size of the columns or rows of the matrix.

If the number of the plurality of REGs included in each of the at leastone CCE corresponds to a product of a value of the information on thesize of the matrix and a value of the information on the REG bundlesize, the one or more REG bundles may be mapped to physical resources ata regular interval.

If a value of the information on the size of the matrix is equal to thenumber of REG bundles included in each of the at least one CCE, the oneor more REG bundles may be mapped to physical resources at a regularinterval.

The received information on the REG bundle size may be determined basedon the number of symbols of a control resource set (CORESET) configuredin the UE.

In another aspect of the present invention, provided herein is a userequipment (UE) for receiving a downlink control channel in a wirelesscommunication system including a radio frequency (RF) module fortransmitting and receiving a radio signal to and from a base station,and a processor connected to the RF module and configured to receiveinformation on a resource element group (REG) bundle size andinformation on a size of a matrix for interleaving a plurality of REGsconfiguring at least one control channel element (CCE) through a higherlayer, to determine the matrix for interleaving the plurality of REGsbased on the information on the size of the matrix and the informationon the REG bundle size, to interleave the plurality of REGs bundled intoone or more REG bundles according to the REG bundle size using thematrix, and to receive the downlink control channel based on theplurality of interleaved REGs.

The information on the size of the matrix may be information on a sizeof rows or columns of the matrix.

The size of the columns or rows of the matrix may be determined based onthe size of the rows or columns of the matrix and the number of REGbundles included in a control resource set (CORESET) configured in theUE.

If the determined size of the columns or rows of the matrix is not aninteger, an integer having a minimum value among integers greater thanthe determined size of the columns or rows of the matrix may bedetermined as the size of the columns or rows of the matrix.

If the number of the plurality of REGs included in each of the at leastone CCE corresponds to a product of a value of the information on thesize of the matrix and a value of the information on the REG bundlesize, the one or more REG bundles may be mapped to physical resources ata regular interval.

If a value of the information on the size of the matrix is equal to thenumber of REG bundles included in each of the at least one CCE, the oneor more REG bundles may be mapped to physical resources at a regularinterval.

The received information on the REG bundle size may be determined basedon the number of symbols of a control resource set (CORESET) configuredin the UE.

Advantageous Effects

According to the present invention, it is possible to increase diversityeffect by dispersing CCEs configuring a downlink control channel on oneor more physical resources.

It will be appreciated by persons skilled in the art that that theeffects that could be achieved with the present invention are notlimited to what has been particularly described hereinabove and otheradvantages of the present invention will be more clearly understood fromthe following detailed description taken in conjunction with theaccompanying drawings.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram for structures of control and user planes of radiointerface protocol between a 3GPP radio access network standard-baseduser equipment and E-UTRAN;

FIG. 2 is a diagram for explaining physical channels used for 3GPPsystem and a general signal transmission method using the physicalchannels;

FIG. 3 is a diagram for a structure of a radio frame in LTE system;

FIG. 4 illustrates a structure of a downlink radio frame in the LTEsystem;

FIG. 5 illustrates resource units used to configure a downlink controlchannel in LTE;

FIG. 6 illustrates a structure of an uplink subframe in the LTE system;

FIG. 7 illustrates examples of a connection scheme between TXRUs andantenna elements.

FIG. 8 illustrates an example of a self-contained subframe structure;

FIG. 9 is a view showing an embodiment of bundling REGs on a time axis;

FIGS. 10 to 13 are views showing embodiments of dispersing REGs based ona time axis;

FIG. 14 is a view showing an embodiment of bundling REGs on a frequencyaxis;

FIGS. 15 to 18 are views showing embodiments of dispersing REGs based ona frequency axis;

FIGS. 19 to 20 are views showing embodiments of mapping REGs to physicalresources;

FIG. 21 is a view showing an embodiment of bundling CCEs;

FIGS. 22 to 27 are views showing embodiments of dispersing REGs inbundle chunk units;

FIG. 28 is a view showing an embodiment of a method of configuring acandidate downlink control channel; and

FIG. 29 is a block diagram of a communication apparatus according to anembodiment of the present disclosure.

BEST MODE

The configuration, operation, and other features of the presentdisclosure will readily be understood with embodiments of the presentdisclosure described with reference to the attached drawings.Embodiments of the present disclosure as set forth herein are examplesin which the technical features of the present disclosure are applied toa 3rd Generation Partnership Project (3 GPP) system.

While embodiments of the present disclosure are described in the contextof Long Term Evolution (LTE) and LTE-Advanced (LTE-A) systems, they arepurely exemplary. Therefore, the embodiments of the present disclosureare applicable to any other communication system as long as the abovedefinitions are valid for the communication system.

The term ‘Base Station (BS)’ may be used to cover the meanings of termsincluding Remote Radio Head (RRH), evolved Node B (eNB or eNode B),Reception Point (RP), relay, etc.

FIG. 1 illustrates control-plane and user-plane protocol stacks in aradio interface protocol architecture conforming to a 3GPP wirelessaccess network standard between a User Equipment (UE) and an EvolvedUMTS Terrestrial Radio Access Network (E-UTRAN). The control plane is apath in which the UE and the E-UTRAN transmit control messages to managecalls, and the user plane is a path in which data generated from anapplication layer, for example, voice data or Internet packet data istransmitted.

A PHYsical (PHY) layer at Layer 1 (L1) provides information transferservice to its higher layer, a Medium Access Control (MAC) layer. ThePHY layer is connected to the MAC layer via transport channels. Thetransport channels deliver data between the MAC layer and the PHY layer.Data is transmitted on physical channels between the PHY layers of atransmitter and a receiver. The physical channels use time and frequencyas radio resources. Specifically, the physical channels are modulated inOrthogonal Frequency Division Multiple Access (OFDMA) for Downlink (DL)and in Single Carrier Frequency Division Multiple Access (SC-FDMA) forUplink (UL).

The MAC layer at Layer 2 (L2) provides service to its higher layer, aRadio Link Control (RLC) layer via logical channels. The RLC layer at L2supports reliable data transmission. RLC functionality may beimplemented in a function block of the MAC layer. A Packet DataConvergence Protocol (PDCP) layer at L2 performs header compression toreduce the amount of unnecessary control information and thusefficiently transmit Internet Protocol (IP) packets such as IP version 4(IPv4) or IP version 6 (IPv6) packets via an air interface having anarrow bandwidth.

A Radio Resource Control (RRC) layer at the lowest part of Layer 3 (orL3) is defined only on the control plane. The RRC layer controls logicalchannels, transport channels, and physical channels in relation toconfiguration, reconfiguration, and release of radio bearers. A radiobearer refers to a service provided at L2, for data transmission betweenthe UE and the E-UTRAN. For this purpose, the RRC layers of the UE andthe E-UTRAN exchange RRC messages with each other. If an RRC connectionis established between the UE and the E-UTRAN, the UE is in RRCConnected mode and otherwise, the UE is in RRC Idle mode. A Non-AccessStratum (NAS) layer above the RRC layer performs functions includingsession management and mobility management.

DL transport channels used to deliver data from the E-UTRAN to UEsinclude a Broadcast Channel (BCH) carrying system information, a PagingChannel (PCH) carrying a paging message, and a Shared Channel (SCH)carrying user traffic or a control message. DL multicast traffic orcontrol messages or DL broadcast traffic or control messages may betransmitted on a DL SCH or a separately defined DL Multicast Channel(MCH). UL transport channels used to deliver data from a UE to theE-UTRAN include a Random Access Channel (RACH) carrying an initialcontrol message and a UL SCH carrying user traffic or a control message.Logical channels that are defined above transport channels and mapped tothe transport channels include a Broadcast Control Channel (BCCH), aPaging Control Channel (PCCH), a Common Control Channel (CCCH), aMulticast Control Channel (MCCH), a Multicast Traffic Channel (MTCH),etc.

FIG. 2 illustrates physical channels and a general method fortransmitting signals on the physical channels in the 3GPP system.

Referring to FIG. 2, when a UE is powered on or enters a new cell, theUE performs initial cell search (S201). The initial cell search involvesacquisition of synchronization to an eNB. Specifically, the UEsynchronizes its timing to the eNB and acquires a cell Identifier (ID)and other information by receiving a Primary Synchronization Channel(P-SCH) and a Secondary Synchronization Channel (S-SCH) from the eNB.Then the UE may acquire information broadcast in the cell by receiving aPhysical Broadcast Channel (PBCH) from the eNB. During the initial cellsearch, the UE may monitor a DL channel state by receiving a DownLinkReference Signal (DL RS).

After the initial cell search, the UE may acquire detailed systeminformation by receiving a Physical Downlink Control Channel (PDCCH) andreceiving a Physical Downlink Shared Channel (PDSCH) based oninformation included in the PDCCH (S202).

If the UE initially accesses the eNB or has no radio resources forsignal transmission to the eNB, the UE may perform a random accessprocedure with the eNB (S203 to S206). In the random access procedure,the UE may transmit a predetermined sequence as a preamble on a PhysicalRandom Access Channel (PRACH) (S203 and S205) and may receive a responsemessage to the preamble on a PDCCH and a PDSCH associated with the PDCCH(S204 and S206). In the case of a contention-based RACH, the UE mayadditionally perform a contention resolution procedure.

After the above procedure, the UE may receive a PDCCH and/or a PDSCHfrom the eNB (S207) and transmit a Physical Uplink Shared Channel(PUSCH) and/or a Physical Uplink Control Channel (PUCCH) to the eNB(S208), which is a general DL and UL signal transmission procedure.Particularly, the UE receives Downlink Control Information (DCI) on aPDCCH. Herein, the DCI includes control information such as resourceallocation information for the UE. Different DCI formats are definedaccording to different usages of DCI.

Control information that the UE transmits to the eNB on the UL orreceives from the eNB on the DL includes a DL/UL ACKnowledgment/NegativeACKnowledgment (ACK/NACK) signal, a Channel Quality Indicator (CQI), aPrecoding Matrix Index (PMI), a Rank Indicator (RI), etc. In the 3GPPLTE system, the UE may transmit control information such as a CQI, aPMI, an RI, etc. on a PUSCH and/or a PUCCH.

FIG. 3 illustrates a structure of a radio frame used in the LTE system.

Referring to FIG. 3, a radio frame is 10 ms (327200×Ts) long and dividedinto 10 equal-sized subframes. Each subframe is lms long and furtherdivided into two slots. Each time slot is 0.5 ms (15360×Ts) long.Herein, Ts represents a sampling time and Ts=1/(15 kHz×2048)=3.2552×10−8(about 33ns). A slot includes a plurality of Orthogonal FrequencyDivision Multiplexing (OFDM) symbols or SC-FDMA symbols in the timedomain by a plurality of Resource Blocks (RBs) in the frequency domain.In the LTE system, one RB includes 12 subcarriers by 7 (or 6) OFDMsymbols. A unit time during which data is transmitted is defined as aTransmission Time Interval (TTI). The TTI may be defined in units of oneor more subframes. The above-described radio frame structure is purelyexemplary and thus the number of subframes in a radio frame, the numberof slots in a subframe, or the number of OFDM symbols in a slot mayvary.

FIG. 4 illustrates exemplary control channels included in a controlregion of a subframe in a DL radio frame.

Referring to FIG. 4, a subframe includes 14 OFDM symbols. The first oneto three OFDM symbols of a subframe are used for a control region andthe other 13 to 11 OFDM symbols are used for a data region according toa subframe configuration. In FIG. 4, reference characters R1 to R4denote RSs or pilot signals for antenna 0 to antenna 3. RSs areallocated in a predetermined pattern in a subframe irrespective of thecontrol region and the data region. A control channel is allocated tonon-RS resources in the control region and a traffic channel is alsoallocated to non-RS resources in the data region. Control channelsallocated to the control region include a Physical Control FormatIndicator Channel (PCFICH), a Physical Hybrid-ARQ Indicator Channel(PHICH), a Physical Downlink Control Channel (PDCCH), etc.

The PCFICH is a physical control format indicator channel carryinginformation about the number of OFDM symbols used for PDCCHs in eachsubframe. The PCFICH is located in the first OFDM symbol of a subframeand configured with priority over the PHICH and the PDCCH. The PCFICHincludes 4 Resource Element Groups (REGs), each REG being distributed tothe control region based on a cell Identity (ID). One REG includes 4Resource Elements (REs). An RE is a minimum physical resource defined byone subcarrier by one OFDM symbol. The PCFICH is set to 1 to 3 or 2 to 4according to a bandwidth. The PCFICH is modulated in Quadrature PhaseShift Keying (QPSK).

The PHICH is a physical Hybrid-Automatic Repeat and request (HARQ)indicator channel carrying an HARQ ACK/NACK for a UL transmission. Thatis, the PHICH is a channel that delivers DL ACK/NACK information for ULHARQ. The PHICH includes one REG and is scrambled cell-specifically. AnACK/NACK is indicated in one bit and modulated in Binary Phase ShiftKeying (BPSK). The modulated ACK/NACK is spread with a Spreading Factor(SF) of 2 or 4. A plurality of PHICHs mapped to the same resources forma PHICH group. The number of PHICHs multiplexed into a PHICH group isdetermined according to the number of spreading codes. A PHICH (group)is repeated three times to obtain a diversity gain in the frequencydomain and/or the time domain.

The PDCCH is a physical DL control channel allocated to the first n OFDMsymbols of a subframe. Herein, n is 1 or a larger integer indicated bythe PCFICH. The PDCCH occupies one or more CCEs. The PDCCH carriesresource allocation information about transport channels, PCH andDL-SCH, a UL scheduling grant, and HARQ information to each UE or UEgroup. The PCH and the DL-SCH are transmitted on a PDSCH. Therefore, aneNB and a UE transmit and receive data usually on the PDSCH, except forspecific control information or specific service data.

Information indicating one or more UEs to receive PDSCH data andinformation indicating how the UEs are supposed to receive and decodethe PDSCH data are delivered on a PDCCH. For example, on the assumptionthat the Cyclic Redundancy Check (CRC) of a specific PDCCH is masked byRadio Network Temporary Identity (RNTI) “A” and information about datatransmitted in radio resources (e.g. at a frequency position) “B” basedon transport format information (e.g. a transport block size, amodulation scheme, coding information, etc.) “C” is transmitted in aspecific subframe, a UE within a cell monitors, that is, blind-decodes aPDCCH using its RNTI information in a search space. If one or more UEshave RNTI “A”, these UEs receive the PDCCH and receive a PDSCH indicatedby “B” and “C” based on information of the received PDCCH.

FIG. 5 illustrates resource units used to configure a downlink controlchannel in LTE. FIG. 5(a) shows a case in which the number of transmit(Tx) antennas is 1 or 2 and FIG. 5(b) shows a case in which the numberof Tx antenna is 4. Although a different RS pattern is used according tothe number of Tx antennas, REs are configured for a DL control channelin the same manner.

Referring to FIG. 5, a basic resource unit of a DL control channel is anREG. The REG includes four contiguous REs except for REs carrying RSs.REGs are marked with bold lines in FIG. 5. A PCFICH and a PHICH include4 REGs and 3 REGs, respectively. A PDCCH is configured in units of acontrol channel element (CCE), each CCE including 9 REGs.

To determine whether a PDCCH including L CCEs is transmitted to a UE,the UE is configured to monitor M^((L)) (≥L) CCEs that are arrangedcontiguously or according to a predetermined rule. L that the UE shouldconsider for PDCCH reception may be a plural value. CCE sets that the UEshould monitor to receive a PDCCH are referred to as a search space. Forexample, LTE defines search spaces as illustrated in Table 1.

TABLE 1 Number of Search space S_(k) ^((L)) PDCCH Type Aggregation levelL Size [in CCEs] candidates M^((L)) UE- 1 6 6 specific 2 12 6 4 8 2 8 162 Common 4 16 4 8 16 2

In Table 1, L is a CCE aggregation level, that is, the number of CCEs ina PDCCH, S_(k) ^((L)) is a search space with CCE aggregation level L,and M^((L)) is the number of candidate PDCCHs to be monitored in thesearch space with CCE aggregation level L.

Search spaces are classified into a UE-specific search space accessibleonly by a specific UE and a common search space accessible by all UEswithin a cell. A UE monitors common search spaces with CCE aggregationlevels 4 and 8 and UE-specific search spaces with CCE aggregation levels1, 2, 4, and 8. A common search space and a UE-specific search space mayoverlap each other.

For each CCE aggregation level, the position of the first CCE (a CCEhaving the smallest index) of a PDCCH search space allocated to a UEchanges every subframe. This is called PDCCH search space hashing.

A CCE may be distributed across a system band. More specifically, aplurality of logically contiguous CCEs may be input to an interleaverand the interleaver may permute the sequence of 2 0 the input CCEs on anREG basis. Accordingly, the time/frequency resources of one CCE aredistributed physically across the total time/frequency region of thecontrol region of a subframe. As a control channel is configured inunits of a CCE but interleaved in units of an REG, frequency diversitygain and interference randomization gain may be maximized.

FIG. 6 illustrates a structure of a UL subframe in the LTE system.

Referring to FIG. 6, a UL subframe may be divided into a control regionand a data region. A Physical Uplink Control Channel (PUCCH) includingUplink Control Information (UCI) is allocated to the control region anda Physical uplink Shared Channel (PUSCH) including user data isallocated to the data region. The middle of the subframe is allocated tothe PUSCH, while both sides of the data region in the frequency domainare allocated to the PUCCH. Control information transmitted on the PUCCHmay include an HARQ ACK/NACK, a CQI representing a downlink channelstate, an RI for Multiple Input Multiple Output (MIMO), a SchedulingRequest (SR) requesting UL resource allocation. A PUCCH for one UEoccupies one RB in each slot of a subframe. That is, the two RBsallocated to the PUCCH are frequency-hopped over the slot boundary ofthe subframe. Particularly, PUCCHs with m=0, m=1, and m=2 are allocatedto a subframe in FIG. 6.

Hereinafter, channel state information (CSI) reporting will be describedbelow. In the current LTE standard, there are two MIMO transmissionschemes, open-loop MIMO operating without channel information andclosed-loop MIMO operating with channel information. Particularly in theclosed-loop MIMO, each of an eNB and a UE may perform beamforming basedon CSI to obtain the multiplexing gain of MIMO antennas. To acquire CSIfrom the UE, the eNB may command the UE to feed back CSI on a downlinksignal by allocating a PUCCH(Physical Uplink Control CHannel) or aPUSCH(Physical Uplink Shared CHannel) to the UE.

The CSI is largely classified into three information types, RI (RankIndicator), PMI (Precoding Matrix), and CQI (Channel QualityIndication). First of all, the RI indicates rank information of achannel as described above, and means the number of streams that may bereceived by a UE through the same time-frequency resources. Also, sincethe RI is determined by long-term fading of a channel, the RI may be fedback to an eNB in a longer period than a PMI value and a CQI value.

Second, the PMI is a value obtained by reflecting spatialcharacteristics of a channel, and indicates a precoding matrix index ofan eNB, which is preferred by the UE based on a metric such as signal tointerference and noise ratio (SINR). Finally, the CQI is a valueindicating channel strength, and generally means a reception SINR thatmay be obtained by the eNB when the PMI is used.

In the 3GPP LTE-A system, the eNB may configure a plurality of CSIprocesses for the UE, and may be reported CSI for each of the CSIprocesses. In this case, the CSI process includes CSI-RS resource forspecifying signal quality and CSI-IM (interference measurement)resource, that is, IMR (interference measurement resource) forinterference measurement.

Since a wavelength becomes short in the field of Millimeter Wave (mmW),a plurality of antenna elements may be installed in the same area. Inmore detail, a wavelength is 1 cm in a band of 30 GHz, and a total of64(8×8) antenna elements of a 2D array may be installed in a panel of 4by 4 cm at an interval of 0.5 lambda(wavelength). Therefore, a recenttrend in the field of mmW attempts to increase coverage or throughput byenhancing BF (beamforming) gain using a plurality of antenna elements.

In this case, if a transceiver unit (TXRU) is provided to control atransmission power and phase per antenna element, independentbeamforming may be performed for each frequency resource. However, aproblem occurs in that effectiveness is deteriorated in view of costwhen TXRU is provided for all of 100 antenna elements. Therefore, ascheme is considered, in which a plurality of antenna elements aremapped into one TXRU and a beam direction is controlled by an analogphase shifter. Since this analog beamforming scheme may make only onebeam direction in a full band, a problem occurs in that frequencyselective beamforming is not available.

As an intermediate type of digital BF and analog BF, a hybrid BF havingB TXRUs smaller than Q antenna elements may be considered. In this case,although there is a difference depending on a connection scheme of BTXRUs and Q antenna elements, the number of beam directions that enablesimultaneous transmission is limited to B or less.

FIG. 7 illustrates examples of a connection scheme between TXRUs andantenna elements.

(a) of FIG. 7 illustrates that TXRU is connected to a sub-array. In thiscase, the antenna elements are connected to only one TXRU. Unlike (a) ofFIG. 7, (b) of FIG. 7 illustrates that TXRU is connected to all antennaelements. In this case, the antenna elements are connected to all TXRUs.In FIG. 7, W indicates a phase vector multiplied by an analog phaseshifter. That is, a direction of analog beamforming is determined by W.In this case, mapping between CSI-RS antenna ports and TXRUs may be1-to-1 or 1-to-many.

As more communication devices require greater communication capacity,the need of mobile broadband communication more advanced than theconventional RAT (radio access technology) has been issued. Also,massive MTC (Machine Type Communications) technology that providesvarious services anywhere and at any time by connecting a plurality ofdevices and things is one of main issues which will be considered innext generation communication. Furthermore, a communication systemdesign considering service/UE susceptible to reliability and latency hasbeen discussed. Considering this status, the introduction of the nextgeneration RAT has been discussed, and the next generation RAT will bereferred to as NewRAT in the present invention.

A self-contained subframe structure shown in FIG. 8 is considered in thefifth generation NewRAT to minimize data transmission latency in a TDDsystem. FIG. 8 illustrates an example of a self-contained subframestructure.

In FIG. 8, oblique line areas indicate downlink control regions andblack colored areas indicate uplink control regions. Areas having nomark may be used for downlink data transmission or uplink datatransmission. In this structure, downlink transmission and uplinktransmission are performed in due order within one subframe, wherebydownlink data may be transmitted and uplink ACK/NACK may be receivedwithin the subframe. As a result, the time required for datare-transmission may be reduced when an error occurs in datatransmission, whereby latency of final data transfer may be minimized.

In this self-contained subframe structure, a time gap for switching froma transmission mode to a reception mode or vice versa is required forthe eNB and the UE. To this end, some OFDM symbols (OS) at the time whena downlink is switched to an uplink in the self-contained subframestructure are set to a guard period.

Examples of the self-contained subframe type that may be configured inthe system operating based on the NewRAT may consider four subframetypes as follows.

downlink control period+downlink data period+GP+uplink control period

downlink control period+downlink data period

downlink control period+GP+uplink data period+uplink control period

downlink control period+GP+uplink data period

FIG. 8(b) shows subframe types of (1) and (3) among the above-describedfour subframe types.

In such a structure, one or more symbols may be allocated for thedownlink control channel and control information may be transmittedusing the downlink control channel. At this time, a resource elementgroup (REG) which is a minimum unit for transmitting control informationmay be configured, and a predetermined number of REGs may be grouped toconfigure a control channel element (CCE). For example, the REG may beconfigured in units of one resource block (RB) and the CCE may beconfigured in units of 6 REGs.

Meanwhile, upon configuring the CCE, REGs may be dispersed on physicalresources for diversity effect. At this time, an interleaver may beused.

In the present invention, a method of configuring an interleaver on adownlink control channel which may be considered in NewRAT is proposed.

Method of Designing Interleaver Based on Bundling Between REGs

In NewRAT, unlike the existing LTE system, a COntrol REsource SET(CORESET) may be specified for each user and/or each user group. Inaddition, only a UE-specific RS may be transmitted instead of acell-specific RS (reference signal). In this case, a plurality of REGsmay be continuously bundled and arranged and channel estimation may beperformed using all UE-specific RSs present in bundle units, therebyincreasing channel estimation performance.

For example, if one CCE is composed of six REGs, the REGs may be bundledin two or three units. The REG bundling unit may be predefined in asystem or signaled from a base station to a user through higher layersignaling and/or through physical layer signaling.

Meanwhile, when bundling between the REGs is performed, the REGs may bebundled on a time axis, a frequency axis, or time and frequency axes.When a plurality of REGs is bundled, since the plurality of bundled REGsmay be continuously arranged on actual physical resources, theinterleaver should be applied in bundled REG units.

Although the case where REGs configuring a CCE are bundled on a timeaxis or a frequency axis is described in the present invention, the REGsmay be bundled on the time axis and the frequency axis according to thenumber of REG bundles. For example, if the REG bundling unit is 4, twoREGs are bundled on the time axis and the two REGs bundled on the timeaxis may be bundled on the frequency axis.

In this case, the bundle unit index described in the present inventionmay correspond to a plurality of REG groups bundled on the time axis andthe frequency axis.

Embodiment 1: Method of Designing Interleaver when REGs are Bundled onTime Axis.

If a CORESET is composed of two or more symbols on the time axis,bundling REGs on the time axis may be considered. At this time, as shownin FIG. 9, the time-axis bundling size of the REGs may be configured tobe equal to the duration of the CORESET.

For example, if the number of REGs configuring one CCE is 6, the REGsmay be dispersed on the frequency axis within one symbol without beingbundled on the time axis when the CORESET duration is composed of 1symbol, and the time-axis bundling size of the REGs may be set to 2 or 3and then the REGs may be dispersed on the frequency axis in bundle unitswhen the CORESET duration is composed of two symbols or three symbols.

At this time, the REG bundling size may be set differently from theCORESET duration. At this time, the REG bundling size may be predefinedin a system, may be signaled from the base station to the UE throughhigher layer signaling and/or physical layer signaling, or may bedetermined according to the configuration (e.g., CORESET duration) ofthe CORESET.

Similarly, whether REG bundling is made on the time axis or thefrequency axis may be predefined in a system, may be signaled from thebase station to the UE through higher layer signaling and/or physicallayer signaling, may be determined according to the configuration (e.g.,CORESET duration) of the CORESET, or may be determined according to theCCE bundling configuration.

At this time, as the method of dispersing the REGs, which are bundled onthe time axis, on the frequency axis, the REGs may be dispersed inbundle units as much as possible at regular intervals in the bandwidthof the CORESET as shown in FIG. 9 or may be randomly dispersed in bundleunits at irregular intervals. However, when bundling is not performed,the REGs may be dispersed in REG units.

<Embodiment 1-1: Method of Randomly Dispersing REGs in Bundle Units>

A block interleaver may be used in order to randomly disperse REGs inbundle units. For example, if the maximum number of REG bundles whichmay be included in the CORESET configured for the UE is m, the logicalindices of REG bundles may be sequentially mapped to a matrix, thenumber of columns of which is fixed to k, row by row.

At this time, the number 1 of rows of the matrix is a minimum integersatisfying m≤l×k. If m≤l×k, an l×k matrix may be configured by fillingthe end of a last row with l×k−m null values. Thereafter, permutation isapplied column by column using a predefined column permutation patternand then elements are sequentially arranged column by column startingfrom the element of a first column, thereby interleaving the logicalindices of the REG bundles.

At this time, when the interleaved indices of the REG bundles are mappedin the physical domain, the logical indices of a plurality of REGsoriginally grouped in REG bundle units are sequentially mapped on thetime axis, thereby randomly dispersing the REGs to the CORESET in bundleunits in consideration of the time-axis bundle unit.

Here, the column size of the interleaved matrix and the columnpermutation pattern may be predefined in the system or may be signaledfrom the base station to the UE through higher layer signaling and/orphysical layer signaling.

FIG. 10 illustrates the detailed example of the above description.Referring to FIG. 10, one CCE includes 6 REGs, an REG bundle unit is 2,m=6, k=5 and l=2, and the column permutation pattern is <4,2,1,3,0>.

In the example of FIG. 10, since the number of REGs is extremely limitedin order to facilitate understanding of the present invention,dispersing of the REG bundles is limited.

However, since the CORESET size actually specified in the system issufficiently large, the REG bundle units may be sufficiently randomlydispersed on the frequency axis.

Meanwhile, although the number of columns is described as being fixed inFIG. 10 and the above-described embodiment, the above-describedembodiment is applicable to the case where the number of rows is fixed.

To describe this in detail, a method of dispersing REGs in bundle unitsbased on a matrix, the number of rows of which is fixed, will bedescribed with reference to FIG. 11.

Referring to FIG. 11, if the maximum number of REG bundles which may beincluded in the CORESET configured for the UE is m, the logical indicesof the REG bundles may be mapped to a matrix, the number of rows ofwhich is fixed to k, column by column.

In FIG. 11, since one CCE includes 6 REGs, the REG bundle unit is 2, andm=6 and k=5, the number 1 of columns of the matrix satisfying m≤l×k is2.

In addition, since m<l×k, a k×l matrix, that is, a 5×2 matrix, may beconfigured by filling the end of a last column with l×k−m=2×5−6=4 nullvalues. Thereafter, permutation is applied row by row using a predefinedrow permutation pattern and then elements are sequentially arranged rowby row starting from the element of a first row, thereby interleavingthe logical indices of the REG bundles.

At this time, when the interleaved indices of the REG bundles are mappedin the physical domain, the logical indices of a plurality of REGsoriginally grouped in REG bundle units are sequentially mapped on thetime axis, thereby randomly dispersing the REGs to the CORESET in bundleunits in consideration of the time-axis bundle unit.

Here, the row size of the interleaved matrix and the row permutationpattern may be predefined in the system or may be signaled from the basestation to the UE through higher layer signaling and/or physical layersignaling.

<Embodiment 1-2: Method of Dispersing REGs in Bundle Units at RegularInterval>

In order to maximize the frequency diversity effect on the frequencyaxis, the REG bundle units may be configured to be spread as evenly aspossible in the bandwidth of the CORESET. In such a configuration, thenumber of columns of the matrix in the block interleaver operation maybe set to the number of units corresponding to one CCE (e.g., REGbundles corresponding to one CCE) and the column or row permutationprocess may not be performed. Here, the column or row permutationprocess being not performed may mean that the column or row permutationpattern is <0,1,2,3,4>based on the Embodiment 1-1.

In FIG. 12, if one CCE includes 6 REGs and the REG bundling unit is 2,since the number of REG bundle indices corresponding to one CCE is 3,the number of columns of the matrix may be set to 3 to be equal to thenumber of REG bundles corresponding to one CCE.

That is, since the number of columns is 3, the number of rows is 2. Thisis because the number of is ls satisfying m×l×k is 2 (m=6 and 1=3).Thereafter, the logical indices of the REG bundles may be sequentiallymapped to the matrix row by row and the elements may be sequentiallyarranged column by column starting from the element of the first column,thereby interleaving the logical indices of the REG bundles.

At this time, when the interleaved indices of the REG bundles are mappedin the physical domain, the logical indices of a plurality of REGsoriginally grouped in REG bundle units are sequentially mapped on thetime axis, thereby dispersing the REGs to the CORESET in bundle units ata regular interval in consideration of the time-axis bundle unit.

Referring to FIG. 13, when the number of rows is 3, the number ofcolumns is 2. Thereafter, the logical indices of the REG bundles may besequentially mapped to the matrix column by column and the elements maybe sequentially arranged row by row starting from the element of thefirst row, thereby interleaving the logical indices of the REG bundles.

At this time, when the interleaved indices of the REG bundles are mappedin the physical domain, the logical indices of a plurality of REGsoriginally grouped in REG bundle units are sequentially mapped on thetime axis, thereby dispersing the REGs to the CORESET in bundle units ata regular interval in consideration of the time-axis bundle unit.

Meanwhile, as described in Embodiment 1-1, the column size of theinterleaving of FIG. 12 or the row size of the interleaving matrix ofFIG. 13 may be predefined in the system or may be signaled from the basestation to the UE through higher layer signaling and/or physical layersignaling.

Embodiment 2: Method of Designing Interleaver when REGs are Bundled onFrequency Axis

If REGs are bundled on the frequency axis, as shown in FIG. 14, evenwhen the CORESET includes a plurality of symbols, REGs configuring oneCCE may be present in one symbol.

<Embodiment 2-1: Method of Randomly Dispersing REGs in Bundle Units>

The method described in Embodiment 1-1 is applicable to the method ofrandomly dispersing the REGs in bundle units without change. As shown inFIGS. 15 and 16, when the interleaved bundle unit indices are mapped tophysical resources, the indices of the REGs included in one bundle unitmay be continuously mapped on the frequency axis, thereby randomlydispersing the REGs on the frequency axis while maintaining the bundleunit.

<Embodiment 2-2: Method of Randomly Dispersing REGs in Bundle Units atRegular Interval>

The method described in Embodiment 1-2 is applicable to the method ofdispersing the REGs in bundle units at a regular interval withoutchange. As shown in FIGS. 17 and 18, when the interleaved bundle unitindices are mapped to physical resources, the indices of the REGsincluded in one bundle unit may be continuously mapped on the frequencyaxis, thereby dispersing the REGs on the frequency at a regular intervalwhile maintaining the bundle unit.

Embodiment 3: Case where Bandwidth of CORESET is not Multiple of REGBundle Unit.

The bandwidth of the CORESET may be configured to have a size which isnot a multiple of the number of REGs configuring the REG bundle unit. Inthis case, the remaining region which cannot configure the REG bundleunit may be configured to be located at the front or back of thebandwidth region of the physical domain in which the CORESET isconfigured.

At this time, when interleaving is performed based on the REG bundleunit index, the REG bundle unit index is further indexed inconsideration of the remaining region which cannot configure the REGbundle unit and then interleaving is performed. Rate matching may beperformed with respect to the logical REG bundle unit index mapped tothe physical resource located at the front or back of the bandwidthregion in which the CORESET is configured.

That is, in the situation shown in FIG. 19, rate matching may beperformed with respect to control information corresponding to logicalREG bundle unit index #1.

Meanwhile, as shown in FIG. 20, the remaining region which cannotconfigure the REG bundle unit may be configured to be located at thefront or back of the bandwidth region of the physical domain in whichthe CORESET is configured, and the REG bundle unit indices excluding thecorresponding region are indexed to perform interleaving. That is, evenwhen mapping is performed in the physical domain through interleaving,the corresponding region may not be used.

If the CORESET is equally set among different base station or cells andthe bandwidth of the CORESET is set to a size which is not a multiple ofthe number of REGs configuring the REG bundle unit, the remaining regionwhich cannot configure the REG bundle unit may be interleaved using theabove-described method and may be used to reduce inter-cell interferenceinstead of being used to map the control information. For example, asshown in FIG. 20, a value v_(shift) may be set using cell-specificinformation such as a cell ID and the bandwidths of the CORESETs ofdifferent cells are differently set.

Meanwhile, if there is no remaining region, that is, if the bandwidth ofthe CORESET is set to a size which is a multiple of the number of REGsconfiguring the REG bundle unit, the position and/or size of thebandwidth of the CORESET may be differently set for each cell in orderto reduce inter-cell interference.

Method of Applying Bundling Between CCEs

If CCE aggregation is performed, the REGs may be bundled on thefrequency axis while being bundled on the time axis. Therefore,frequency-axis bundling may be performed between REG bundle unitsincluded in different CCEs.

Similarly, if CCE aggregation is performed, the REGs may be bundled onthe time axis between the REG bundle units included in different CCEswhile being bundled on the frequency axis.

In this case, a CCE bundle unit in which bundling between CCEs isperformed may be set. At this time, the size of the CCE bundling unitand/or whether CCE bundling is performed on the time axis or thefrequency axis may be predefined in the system, may be signaled from thebase station to the UE through higher layer signaling and/or physicallayer signaling, or may be set according to the CORESET configuration(e.g., CORESET duration). Alternatively, whether CCE bundling isperformed on the time axis or the frequency axis may be determinedaccording to the REG bundling configuration. That is, if REG bundling isperformed on the time axis, CCE bundling may be performed on thefrequency axis. In contrast, if REG bundling is performed on thefrequency axis, CCE bundling may be performed on the time axis

FIG. 21 shows an embodiment in which the CCE bundling unit is 2 on thefrequency axis in a state in which REGs configure an REG bundle unit onthe time axis by the length of the CORESET duration.

Embodiment 4: Method of Performing Interleaving at Random Intervalsbetween Bundle Chunks

An example of randomly performing interleaving in bundle chunk unitswill be described with reference to FIGS. 22 and 23. The principle ofthe method of randomly performing interleaving in bundle chunk units maybe equal to that of the method of performing interleaving in REG bundleunits of Embodiment 1-1 and Embodiment 1-2.

However, in FIG. 22, REG bundle units belonging to different CCEs to bebundled may be grouped to configure a new bundling unit. For example, ifthe size of each of the REG bundle unit and the CCE bundle unit is 2,the indices of the logical REGs configuring logical CCE index 0 may be0, 1, 2, 3, 4 and 5 and the indices of the logical REGs configuringlogical CCE index 1 may be 6, 7, 8, 9, 10 and 11.

In this case, since the size of the REG bundle unit is 2, CCE 0 may beconfigured in REG bundle units of (0, 1), (2, 3) and (4, 5) and CCE1 maybe configured in REG bundle units of (6, 7), (8, 9) and (10, 11). Atthis time, since the size of the CCE bundle unit is 2, the REG bundleunits belonging to the respective CCEs may form a pair such that {(0,1), (6, 7)}, {(2, 3), (8, 9)} and {(4, 5), (10, 11)} configurerespective new bundle chunks. Thereafter, if a new index is indexed intoeach of the bundle chunks, an interleaver is applied based on theindexes and bundling is applied to the CCEs and the REGs, the CCEs andthe REGs may be dispersed on the frequency axis in bundle units.

For example, if bundling between the REGs is performed on the time axisand bundling between the CCEs is performed on the frequency axis, wheninterleaved bundle chunk indices are mapped to the physical resources,the REG index belonging to the REG bundle index in the bundle chunk maybe mapped on the time axis in the corresponding region and the REGbundles may be mapped on the frequency axis.

In contrast, if bundling between the REGs is performed on the frequencyaxis and bundling between the CCEs is performed on the time axis, theREG index belonging to the REG bundle index in the bundle chunk may bemapped on the frequency axis in the corresponding region and the REGbundles may be mapped on the time axis. The size of the columns or rowsof the interleaved matrix and the column or row permutation pattern maybe predefined in the system or may be signaled from the base station tothe UE through higher layer signaling and/or physical layer signaling.

Embodiment 5: Method of Performing Interleaving between Bundle Chunks atRegular Interval

An embodiment of performing interleaving between bundle chunks at aregular interval will be described with reference to FIGS. 24 and 25.When the size of the columns or rows of the interleaver matrix is set tothe number of bundle chunk unit indices corresponding to the CCEbundling unit and column or row permutation is not applied, as shown inFIGS. 24 and 25, interleaving between bundle chunks may be performed ata regular interval.

When interleaving between bundle chunks is performed at the regularinterval, if the CCE aggregation size and the CCE bundling size aredifferently set, interleaving may be performed such that the bundlechunks are further dispersed on the physical resources in CCE bundlingsize units.

For example, the indices may be indexed in CCE bundle units for thelogical CCE indexes and interleaving may be applied to the CCE bundleunits. Thereafter, after interleaving is performed based on the CCEbundle unit, when the logical indices of the CCEs belonging to the CCEbundle unit are listed, it is possible to configure interleaved logicalCCE indices. When the interleaved logical CCE indices are associatedwith the logical CCE indices described in Embodiments 1 to 2, the sameresult as the embodiments of FIGS. 26 and 27 can be obtained.

At this time, the number of columns or rows of the matrix forinterleaving the CCE bundle unit indices may be set to the number of CCEbundle unit indices corresponding to the CCE aggregation level. Inaddition, the REG indices corresponding to the interleaved logical CCEindices may be listed to configure interleaved logical REG indices andthe REG bundle unit indices may be sequentially indexed.

For bundling between CCEs, as in Embodiment 4, REG bundle unitsbelonging to different CCEs to be bundled may be grouped and indexedwith bundle chunk unit indices and interleaving may be performed withrespect to the bundle chunk unit indices. Here, the number of rows orcolumns of the matrix for interleaving the bundle chunk unit indices maybe set to the number of bundle chunk unit indices corresponding to thesize of the CCE bundle unit. In addition, when the interleaved bundlechunk indices are mapped to the physical resources, if bundling betweenREGs is performed on the time axis and bundling between CCEs isperformed on the frequency axis, the REG indices belonging to each REGbundle index in the bundle chunk may be mapped on the time axis in thecorresponding region and the REG bundles may be mapped on the frequencyaxis.

In contrast, if bundling between REGs is performed on the frequency axisand bundling between CCEs is performed on the time axis, the REG indicesbelonging to each REG bundle index in the bundle chunk may be mapped onthe frequency axis in the corresponding region and the REG bundles maybe mapped on the time axis. By this configuration, when the CCEsconfiguring the CCE aggregation level are interleaved, the CCEs may bedispersed on the frequency axis in CCE bundle units as much as possibleat a regular interval, thereby maximizing channel estimation performancethrough bundles and frequency diversity effect through a configurationin which the CCEs are spaced apart from each other in CCE bundle unitson the frequency axis.

Method of Configuring CORESET

Hereinafter, a method of configuring RBs configuring the CORESET will bedescribed independently of the interleaver design. The RBs configuringthe CORESET may be continuously or separately configured in thefrequency region and a combinational index defined in a legacy LTEsystem may be configured through higher layer signaling.

For example, the combinational index shown in Equation 1 may be used.Here, {k_(i)}_(i=0) ^(N) _(RB) ^(X) ⁻¹, (1≤k_(i)≤N_(RB) ^(DL),k_(i)<k_(i+1)) denotes a PRB index, N_(RB) ^(X) ^(p) denotes the numberof RBs of the CORESET p, and N_(RB) ^(DL) denotes the downlink bandwidthof the system.

$\begin{matrix}{r = {\sum\limits_{i = 0}^{N_{RB}^{X_{p}} - 1}{\langle\begin{matrix}{N_{RB}^{DL} - k_{i}} \\{N_{RB}^{X_{p}} - i}\end{matrix}\rangle}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

If the combinational index is configured in consideration of thebundling size, N_(RB) ^(X) ^(P) and N_(RB) ^(DL) of Equation 1 may bereplaced by N_(RB) ^(X) ^(P) /bundling size) and N_(RB) ^(DL)/(bundlingsize). The combinational index derived using the above-described methodmay correspond to RB arrangement of the CORESET continuously orseparately configured in bundle units. For example, if the size of theCORESET is 8 and the bundling size is 2 in an environment in which thedownlink bandwidth is composed of 50 RBs, N_(RB) ^(X) ^(P) /(bundlingsize)=4 and N_(RB) ^(DL)/ undling size)=25 are set to be substitutedinto N_(RB) ^(X) ^(P) and N_(RB) ^(DL) of Equation 1 above, and thederived combinational index may correspond to RB arrangement of theCORESET continuously or separately arranged in the downlink bandwidth inunits of 2 RBs which are the bundle units.

Intra-CCE or inter-CCE REG bundling may be performed as follows.

Referring to FIG. 28, inter-CCE REG bundling will be described. REGbundling may be configured for each CORESET. If one candidate PDCCH iscomposed of CCEs belonging to several CORESETs, a set of inter-CCEbundles may be changed. For example, in the case where the inter-CCE isconfigured over 2 CCEs, if a first CCE and a third CCE of the candidatePDCCH are included in CORESET 1 and a second CCE and a fourth CCE areincluded in CORESET 2 for AL=4, it is assumed that inter-CCE bundlingfor CORESET 1 is performed through 1 and 3 and inter-CCE bundling forCORESET2 is performed through 2 and 3 or the corresponding CCE indexingis performed for each CORESET. However, when the candidate PDCCH iscomposed of CCEs belonging to several CORESETs, the overlaid CCEs may beindexed again and bundling may be performed for each CORESET.

In the case of intra-CCE REG bundling, if one CCE is composed of REGsbelonging to several CORESETs, the following method is applicable tointra-CCE REG bundling.

If the REG bundling size is 6, it may be assumed that one CCE is notmapped to several CORESETs.

Meanwhile, the REG bundling size may be 6/k. k may be the number ofCORESETs, to which one CCE is mapped. REGs having the same index amongthe bundled REGs may be grouped to configure one CCE. If the time-domainREG bundling size is used, since 6/k may not be satisfied, thetime-domain REG bundling may not be assumed if the corresponding methodis used.

Referring to FIG. 29, a communication apparatus 2900 includes aprocessor 2910, a memory 2920, an RF module 2930, a display module 2940,and a User Interface (UI) module 2950.

The communication device 2900 is shown as having the configurationillustrated in FIG. 29, for the convenience of description. Some modulesmay be added to or omitted from the communication apparatus 2900. Inaddition, a module of the communication apparatus 2900 may be dividedinto more modules. The processor 2910 is configured to performoperations according to the embodiments of the present disclosuredescribed before with reference to the drawings. Specifically, fordetailed operations of the processor 2910, the descriptions of FIGS. 1to 28 may be referred to.

The memory 2920 is connected to the processor 2910 and stores anOperating System (OS), applications, program codes, data, etc. The RFmodule 2930, which is connected to the processor 2910, upconverts abaseband signal to an RF signal or downconverts an RF signal to abaseband signal. For this purpose, the RF module 2930 performsdigital-to-analog conversion, amplification, filtering, and frequencyupconversion or performs these processes reversely. The display module2940 is connected to the processor 2910 and displays various types ofinformation. The display module 2940 may be configured as, not limitedto, a known component such as a Liquid Crystal Display (LCD), a LightEmitting Diode (LED) display, and an Organic Light Emitting Diode (OLED)display. The UI module 2950 is connected to the processor 2910 and maybe configured with a combination of known user interfaces such as akeypad, a touch screen, etc.

The embodiments of the present invention described above arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It is obvious tothose skilled in the art that claims that are not explicitly cited ineach other in the appended claims may be presented in combination as anembodiment of the present invention or included as a new claim by asubsequent amendment after the application is filed.

A specific operation described as performed by a BS may be performed byan upper node of the BS. Namely, it is apparent that, in a networkcomprised of a plurality of network nodes including a BS, variousoperations performed for communication with a UE may be performed by theBS, or network nodes other than the BS. The term ‘BS’ may be replacedwith the term ‘fixed station’, ‘Node B’, ‘evolved Node B (eNode B oreNB)’, ‘Access Point (AP)’, etc.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the methods according to exemplaryembodiments of the present invention may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, an embodiment of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. Software code may be stored in a memory unit and executedby a processor. The memory unit is located at the interior or exteriorof the processor and may transmit and receive data to and from theprocessor via various known means.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent disclosure. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of thedisclosure should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

INDUSTRIAL APPLICABILITY

Although the example of applying the method and apparatus fortransmitting the downlink control channel to the fifth-generation NewRATsystem has been described, the present invention is applicable tovarious wireless communication systems in addition to thefifth-generation NewRAT system.

1. A method of receiving a downlink control channel at a user equipment(UE) in a wireless communication system, the method comprising:receiving, from a base station (BS), first information related to aresource element group (REG) bundle size; and receiving, from the BS,the downlink control channel over a control resource set (CORESET) basedon the first information related to the REG bundle size; wherein theCORESET comprises a plurality of REGs that are bundled into one or moreREG bundles based on the REG bundle size, wherein the one or more REGbundles are interleaved within the CORESET based on a interleaver, andwherein the interleaver is determined based on the first informationrelated to the REG bundle size.
 2. The method of claim 1, wherein aduration of the CORESET is configured to be 1, 2, or 3 OrthogonalFrequency Division Multiplexed (OFDM) symbols, wherein the REG bundlesize is related to the duration of the CORESET.
 3. The method of claim1, further comprising: receiving second information relates to one of anumber of rows or a number of columns of the interleaver, and whereinthe other of the number of rows or the number of columns of theinterleaver is determined based on (i) the first information related tothe REG bundle size and (ii) the second information related to the oneof a number of rows or a number of columns of the interleaver.
 4. Themethod of claim 1, wherein the interleaver is determined based on anumber of REG bundles included in the CORESET.
 5. The method of claim 4,wherein the number of REG bundles included in the CORESET is obtained bydividing a total number of REGs included in the CORESET by the REGbundle size.
 6. The method of claim 3, wherein the plurality of REGsconfigure at least one control channel element (CCE), and wherein, basedon a number of REGs included in each of the at least one CCEcorresponding to a product of a value of the second information relatesto one of a number of rows or a number of columns of the interleaver anda value of the first information related to a resource element group(REG) bundle size, the one or more REG bundles are mapped to physicalresources at a regular interval.
 7. The method of claim 3, wherein theplurality of REGs configure at least one control channel element (CCE),and wherein, based on a value of the second information relates to oneof a number of rows or a number of columns of the interleaver beingequal to a number of REG bundles included in each of the at least oneCCE, the one or more REG bundles are mapped to physical resources at aregular interval.
 8. The method of claim 1, wherein the interleaver is amatrix for interleaving REG bundles.
 9. An apparatus configured toreceive a downlink control channel in a wireless communication system,the apparatus comprising: at least one processor; and at least onecomputer memory operably connectable to the at least one processor andstoring instructions that, when executed, cause the at least oneprocessor to perform operations comprising: receiving, from a basestation (BS), first information related to a resource element group(REG) bundle size; and receiving, from the BS, the downlink controlchannel over a control resource set (CORESET) based on the firstinformation related to the REG bundle size; wherein the CORESETcomprises a plurality of REGs that are bundled into one or more REGbundles based on the REG bundle size, wherein the one or more REGbundles are interleaved within the CORESET based on a interleaver, andwherein the interleaver is determined based on the first informationrelated to the REG bundle size.
 10. The apparatus of claim 9, wherein aduration of the CORESET is configured to be 1, 2, or 3 OrthogonalFrequency Division Multiplexed (OFDM) symbols, wherein the REG bundlesize is related to the duration of the CORESET.
 11. The apparatus ofclaim 9, further comprising: receiving second information relates to oneof a number of rows or a number of columns of the interleaver, andwherein other of the number of rows or the number of columns of theinterleaver is determined based on (i) the first information related tothe REG bundle size and (ii) the second information related to the oneof a number of rows or a number of columns of the interleaver.
 12. Theapparatus of claim 9, wherein the interleaver is determined based on anumber of REG bundles included in the CORESET.
 13. The apparatus ofclaim 12, wherein the number of REG bundles included in the CORESET isobtained by dividing a total number of REGs included in the CORESET bythe REG bundle size.
 14. The apparatus of claim 11, wherein theplurality of REGs configure at least one control channel element (CCE),and wherein, based on a number of REGs included in each of the at leastone CCE corresponding to a product of a value of the second informationrelates to one of a number of rows or a number of columns of theinterleaver and a value of the first information related to a resourceelement group (REG) bundle size, the one or more REG bundles are mappedto physical resources at a regular interval.
 15. The apparatus of claim11, wherein the plurality of REGs configure at least one control channelelement (CCE), and wherein, based on a value of the second informationrelates to one of a number of rows or a number of columns of theinterleaver being equal to a number of REG bundles included in each ofthe at least one CCE, the one or more REG bundles are mapped to physicalresources at a regular interval.
 16. The apparatus of claim 9, whereinthe interleaver is a matrix for interleaving REG bundles.
 17. A userequipment (UE) configured to receive a downlink control channel in awireless communication system, the UE comprising: at least onetransceiver; at least one processor; and at least one computer memoryoperably connectable to the at least one processor and storinginstructions that, when executed, cause the at least one processor toperform operations comprising: receiving, through the at least onetransceiver, first information related to a resource element group (REG)bundle size; and receiving, through the at least one transceiver, thedownlink control channel over a control resource set (CORESET) based onthe first information related to the REG bundle size; wherein theCORESET comprises a plurality of REGs that are bundled into one or moreREG bundles based on the REG bundle size, wherein the one or more REGbundles are interleaved within the CORESET based on a interleaver, andwherein the interleaver is determined based on the first informationrelated to the REG bundle size.
 18. A method of transmitting a downlinkcontrol channel at a base station (BS) in a wireless communicationsystem, the method comprising: transmitting, to a user equipment (UE),first information related to a resource element group (REG) bundle size;and transmitting, to the UE, the downlink control channel over a controlresource set (CORESET) based on the first information related to the REGbundle size; wherein the CORESET comprises a plurality of REGs that arebundled into one or more REG bundles based on the REG bundle size,wherein the one or more REG bundles are interleaved within the CORESETbased on a interleaver, and wherein the interleaver is determined basedon the first information related to the REG bundle size.
 19. A basestation (BS) configured to transmit a downlink control channel in awireless communication system, the BS comprising: at least onetransceiver; at least one processor; and at least one computer memoryoperably connectable to the at least one processor and storinginstructions that, when executed, cause the at least one processor toperform operations comprising: transmitting, through the at least onetransceiver, first information related to a resource element group (REG)bundle size; and transmitting, through the at least one transceiver, thedownlink control channel over a control resource set (CORESET) based onthe first information related to the REG bundle size; wherein theCORESET comprises a plurality of REGs that are bundled into one or moreREG bundles based on the REG bundle size, wherein the CORESET comprisesa plurality of REGs that are bundled into one or more REG bundles basedon the REG bundle size, wherein the one or more REG bundles areinterleaved within the CORESET based on a interleaver, and wherein theinterleaver is determined based on the first information related to theREG bundle size.